by Kevin Johnson, USA TODAY

by Kevin Johnson, USA TODAY

Although Aaron Alexis' past is littered with legal and medical red flags, there was nothing that prohibited him from legally obtaining the shotgun earlier this month that he is said to have used in the Navy Yard massacre.

In at least two gun-related incidents - a malicious mischief arrest in Seattle and a separate Fort Worth case in which Alexis suspiciously fired his weapon into the apartment of his next-door neighbor - neither resulted in conviction, leaving his criminal record clear of any felony that would have blocked his recent purchase of the 12-gauge shotgun at a Virginia gun store.

As recently as last month, Alexis also sought treatment for mental illness, a federal law enforcement official said. Yet despite his complaints of paranoid symptoms, in which he reported hearing voices, Alexis still remained eligible to purchase the gun because there is no record that a court had formally declared him mentally ill.

"There is nothing apparent that would have stopped the purchase,'' said the federal official, who is not authorized to comment publicly and spoke on condition of anonymity.

Like last year's mass shootings at a Colorado movie theater and at a Newtown, Conn., school that involved gunmen struggling with illness, Alexis' troubled past also is directing a new focus on the rules that govern access to firearms.

As early as 2004, according to Seattle police, Alexis was arrested for shooting out the tires of another man's vehicle in what Alexis later described to detectives as an anger-fueled "blackout."

According to police reports from the May 6, 2004, incident, witnesses told detectives that Alexis had "stared" at construction workers at the job site every day over the last month prior to pulling a gun from his waistband and shooting out the tires of a Honda vehicle.

Following his arrest, Alexis told detectives that he had been "mocked" by construction workers the morning of the incident and said they had "disrespected him." Alexis also claimed that in his anger-fueled "blackout," he could not remember firing his gun at the vehicle until an hour after the incident.

Alexis also told police he was present during "the tragic events of September 11, 2001" and described "how those events had disturbed him."

Although detectives referred the case to Seattle Municipal Court, the case was not prosecuted and the incident never threatened his eligibility to purchase a gun.

Six years later in Fort Worth, police again encountered Alexis after reports that he had fired a weapon into the apartment of his upstairs neighbor.

"It was determined,'' Tarrant County District Attorney Joe Shannon said in a statement, "that Alexis was cleaning a gun in his apartment when it accidentally went off. No one was injured.''

As in 2004, Alexis' record was not tarnished in Fort Worth and neither was his status as a gun-owner and future buyer.

The federal official familiar with Alexis' background said the Navy Yard shooter most recently sought help for mental illness in August from the Veterans Affairs Department in Rhode Island.

Still, without a court judgment declaring him mentally ill, Alexis only weeks later was able to purchase the shotgun.

"He appears to be somebody who flew under the radar,'' the official said.